The proper differentiation of cells during development requires the differential expression of many genes. A long term goal of this laboratory is to understand how developing organisms control the temporal and cell specific expression of these genes. We propose to study how the cellular slime mold, Dictyostelium discoideum, regulates developmentally controlled enzymes and proteins during early stages of development. We will use genetic appraoches to identify the genes required for the expression of Alpha-mannosidase, one of the earliest developmentally controlled enzymes in this organism. This will be aided by the large number of mutants we have isolated which alter the regulation of this enzyme during development. We are interested in the order in which these genes act to integrate the expression of the marker enzyme into the underlying developmentally program. Molecular studies will be used to determine which step in protein synthesis is utilized by D. discoideum to achieve regulation of the Alpha-mannosidase protein. In vitro translational assays and cDNA hybridization to quantitate the amount of Alpha-mannosidase mRNA will be compared with in vivo synthetic rates to determine the roles of transcription and translation in the regulation of the enzyme. The mutants which alter the regulation of the enzyme will be studied by the same techniques. This will include mutants which fail to induce the enzyme during development and mutants which prematurely cease synthesis of the enzyme. We will also work toward developing DNA mediated transformation techniques which could be used to isolate the regulatory genes for further study.